The publicity hungry and hyper-ambitious Preet Bharara, the US attorney for the Southern District, as well as the heads of the Securities and Exchange Commission and the Commodity Futures Trading Commission, are all longtime Democrats.

Some, like Bharara, are fairly partisan Democrats looking for bigger future jobs. They have much to gain if the investigation doesn’t blow up before Election Day — so it’s pretty convenient that they keep hitting what we’re told are dead ends.

Bharara is rumored to be on the short list of possible successors to Attorney General Eric Holder in a second Obama term, as is FBI chief Robert Mueller.

In other cases, Bharara’s been so eager to drum up good press that’s he’s falsely taken credit for personally recording wiretapped conversations of alleged insider traders. Which makes it odd that he’s said so little about MF Global, the biggest scandal to develop on his watch — especially when we’ve got real victims here, whereas it’s usually impossible to trace investors’ losses in insider-trading cases.